1. Field of the Invention
The present invention relates to a solid-state imaging apparatus including an AD conversion circuit and an imaging system.
2. Description of the Related Art
Some solid-state imaging apparatuses, for example MOS imaging apparatuses, are constituted by an imaging unit and column signal processing circuit, as described in Japanese Patent Laid-Open No. 2008-167004. Japanese Patent Laid-Open No. 2008-167004 describes an arrangement in which a column amplifier circuit and an AD (Analogue to Digital) conversion circuit are mounted in the column signal processing circuit, and AD conversion is performed for each column. This patent literature document discloses a method of amplifying signals of a plurality of systems having different sensitivities, AD-converting them, and then combining them to enlarge the dynamic range without decreasing the S/N ratio. Japanese Patent Laid-Open No. 2010-147614 describes a technique of, in a still image shooting mode, turning on an amplifier to perform high-quality shooting, and in a moving image shooting mode for a monitor, turning off the amplifier to cause a pixel signal to bypass the amplifier, thereby reducing power.
Japanese Patent Laid-Open No. 2010-147614 discloses a technique of switching the input range of an AD converter when the amplifier is turned on/off, and more specifically, halving the amplitude of a ramp waveform and a counter operation when the amplifier is OFF.